Furnace shuts down; LED flashes 6 times repeatedly.

Safety: Turn off power and gas before servicing. Use caution on ladders when inspecting vent terminations.

• Inspect vent piping: Follow the PVC vent and intake pipes from the furnace to the outside. Look for sags, low spots holding water, or joints that have separated. Correct any improper slopes and re-glue loose joints.
• Check condensate trap and drain: On high-efficiency Amana furnaces, remove and flush the condensate trap with warm water. Ensure the drain line is clear and properly sloped to a drain.
• Secure pressure switch tubing: Make sure the rubber tubing is tight on both the pressure switch and inducer ports. Replace brittle or cracked tubing.
• Observe inducer performance: Call for heat and listen for unusual noises or slow startup from the inducer. A weak inducer may need replacement.

If the code recurs after cleaning and securing all venting and condensate components, have a technician measure draft and pressure switch operation.